Method of transmitting MBMS data in an E-UTRAN-system

ABSTRACT

In an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) system Multimedia Broadcast Multicast Service (MBMS) data is transmitted as layered data together with control information comprising information enabling a User Equipment to reconstruct the layered MBMS data.

TECHNICAL FIELD

The present invention relates to a method and a system for transmittingMultimedia Broadcast Multicast Service (MBMS) data in an EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN) system.

BACKGROUND

Multimedia broadcast/multicast services over wireless networks, such ascellular radio networks are becoming widely spread, especially afterthat mobile handheld devices have become capable of receiving multimediacontent via radio networks. However, delivering multimedia over awireless channel to handheld devices has proven to pose a number ofproblems. For example, subscribers may experience different channelquality while receiving the same content. In addition, each user wantsthe highest possible quality of the media.

Layered and scalable codecs have been developed that enable adaptationof the broadcast/multicast stream to changing network conditions. Alayered media consists of a base layer and a number of enhancementlayers each providing quality refinement for the lower layers. The baselayer usually carries the minimum information required by the decoder toprovide a minimum quality for the receivers. Each additional layer mayrefine this minimum perceived quality by, e.g., raising the played outframes per second or extending the screen resolution.

Furthermore, smart bandwidth adaptation can be achieved by forwardingonly the layers that are transmittable by altered network conditions.Also, layered media allows the network to handle a number ofheterogeneous receivers in the same session having, e.g., differentdisplay sizes.

In spite of the existence of these codecs, the adaptation of multimediaflows has to be supported by delivery technologies and access networksas well.

Now, the necessary functions to support Multimedia Broadcast MulticastService (MBMS) transmission in E-UTRAN also sometimes referred to asLong Term Evolution (LTE) networks are being discussed and defined inthe 3GPP standardization body. An important difference compared to theMBMS service delivery in UTRAN comes from the distributed nature of theE-UTRAN architecture. In E-UTRAN the radio resource managementfunctions, including the scheduling are located in the evolved Node Bs(eNodeBs), i.e. in the base stations as opposed to UTRAN, where theradio resource control is located centrally in the Radio NetworkController (RNC). Therefore, for MBMS transmission, which may requirecoordinated and time synchronized transmission from multiple cells (alsocalled Single Frequency Network, i.e., Single Frequency Network (SFN) orMulti Broadcast Single Frequency Network (MBSFN), transmission);additional central control entities have been added to the architecture.A currently proposed MBMS architecture is depicted in FIG. 1.

In FIG. 1 BM-SC is the Broadcast Multicast Service Center, which is theapplication level server providing the multimedia content. The MBMS GateWay (GW) is responsible for the user plane processing of the MBMS data,including such functions as content synchronization and delivering thedata over a multicast IP transport to the relevant eNodeBs. The MBMS GWalso executes control over the start and stop of the services and actsas a mediator between the access agnostic multimedia content sources andthe LTE specific access network.

The MBMS Control Entity (MCE) is a radio resource control entity, whichis responsible mainly for the coordinated allocation of radio resourcesover multiple cells in case of SFN transmission mode.

Currently the standard defines three main transmission methods todeliver MBMS content in LTE networks. These are:

Single Frequency Network (SFN) Transmission:

In this transmission mode, the same multimedia content is transmitted inmultiple cells in a time synchronized fashion such that the physicalsignals arriving from different cells at the User Equipment (UE) can besoft-combined.

Single Cell PTM (Point to Multipoint) Transmission Without Feedback:

In this mode the transmission in a cell is targeted only for the usersin the given cell. In other words, there is no coordination of thetransmission from multiple cells. This also means that a particulareNodeB on its own can control the radio resources the eNodeB spend onthe MBMS transmission, i.e. it is able to perform scheduling. Nofeedback information is available from the UEs regarding the linkquality, success/failure of the reception.

Single Cell PTM Transmission with Feedback:

This mode is the same as Single Cell PTM transmission with thepossibility of sending feedback information from the UEs regarding thelink quality and/or the success/failure of the reception. Utilizingfeedback information from the UEs can help to optimize the transmissionaccordingly and thereby utilize the radio resources more efficiently.

For the transport of MBMS data over the radio interface the standardcurrently defines the MCH transport channel, capable of SFN transmissionand the MBMS Control Channel (MCCH) and the MBMS Traffic Channel (MTCH)logical channels. The MCCH and MTCH logical channels are mapped onto theMCH transport channel. Optionally, it may be possible to map theselogical channels to the normal downlink shared channel (DL-SCH) used todeliver the unicast traffic as well. This may be possible in the singlecell transmission cases, when the SFN transmission mode is not used andtherefore the MCH transport channel can be omitted. The MTCH channelcarries the actual MBMS data. The MCCH channel carries controlinformation necessary for the reception of the MTCH channel. The MCCHincludes session/service identities for sessions to be started, i.e.,announcing service starts, identities for ongoing services, schedulinginformation etc.

Today, there exist a need for a method and a system that is able toimprove the performance of an E-UTRAN radio system.

SUMMARY

It is an object of the present invention to improve existing E-UTRANsystems.

It is another object of the present invention to provide a method,system and a device that provides an extension to existing E-UTRANtransmission modes by which the E-UTRAN system is enabled to provideefficient transmission of layered media streams.

These objects and others are obtained by an E-UTRAN system transmittinglayered MBMS data, the system further having signaling means fortransmitting control information comprising information enabling a UserEquipment (UE) to reconstruct the layered MBMS data.

Hence, in order to obtain a layered/scalable multimedia that can bemulticast in an E-UTRAN MBMS, a signaling unit is provided for examplein the eNodeB, which is adapted to provide control information to a userwhereby the user is enabled to reconstruct a media stream transmitted indifferent layers. For example, the control information may contain, thesession start and signaling that binds together the transmission of thedifferent layers belonging to the same MBMS service, possibly sent withdifferent transmission methods, i.e., in the hybrid case. Thus, bysignaling to a UE where it can find the transmission of the differentlayers belonging to the same service a layered/scalable multimedia canbe transmitted to a UE.

In one embodiment the system is provided with an entity for indicatingto which layer transmitted data belongs to. The entity may for examplebe located in the eNodeB. Such an indication can be sent either on theMBMS point-to-multipoint Control Channel (MCCH) e.g., as part of thescheduling information or could be indicated via L1/L2 control signalingin case the regular DL-SCH is used for MBMS transmission. In case ofL1/L2 control signaling the layer information can be signaled asdifferent group Radio Network Temporary Identities (RNTIs) per layerwhen addressing the recipient of the transmission on the DL-SCH. Yetanother alternative could be to signal the layer information in theMedia Access Control (MAC) header.

In another embodiment feedback information from the UEs on the channelquality is transmitted from the UE to the eNodeB. With such feedbackinformation more optimized layered media delivery can be achieved bothfrom the user-perceived quality and also from the radio resourceutilization point of view.

Also, in case feedback information received from the UEs is used,reference signal power measurement reports (similar to the ones used forhandover) can advantageously be sent from the UEs to the eNodeB to beused as information to decide which layer and/or with which TransportFormat to send.

Hence, by adding support to the signaling channels, protocols, etc.,(e.g. information elements on the MCCH channel, signaling means) foreach of the different MBMS transmission modes defined for E-UTRAN, whichare required for the differentiated handling of the different medialayers during the transmission, it is possible to take into account theradio channel conditions of the receiving UEs when deciding whichcomponents of the media stream to transmit and what transmissionparameters to use such as transmission power, coding, etc.

For example, if the media layers are transmitted in single cell PTMtransmission mode either with or without feedback such as a channelquality report, the eNodeB is enabled to decide which media layers areto be sent and what transport format and transmission power to apply foreach distributed layer. Since the eNodeB can make the decision, the MCEdoes not need to be involved. This can be considered as a de-centralizedsolution. The optimization can further be enhanced if the UEs reporttheir actual experienced radio quality. This feedback information cangive more precise information to the eNodeB on how to distribute themedia layers.

In another example, the existing MBSFN solution and the single cell PTMtransmission mode are combined. In that case it can be advantageous totransmit more important layers, e.g. the base layer, in MBSFN mode andall the other layers are in single cell PTM mode.

In other words, the eNodeB can be set to determine the set ofenhancement layers it wants to broadcast in the own cell based oninformation such as the number of UEs interested in the service, UEchannel quality reports, available cell resources. etc., while a minimumquality is provided by the MBSFN transmission.

The invention also extends to a method for transmitting layered data inan E-UTRAN system and also to a User Equipment adapted to be used in thesystem. In addition the invention extends to a base station configuredto transmit layered data in the E-UTRAN according to the above.

Using the method and system as described herein enables the optimizationof the media stream quality and the used radio resources in an E-UTRANbroadcast system. The quality of the broadcast media can be adjusted tothe actual radio channel quality of the end-users and to the availableresources in the cell. The proposed a method and system further enablesthe E-UTRAN MBMS system to save resources for layered media multicastand better utilize the radio interface.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail by way ofnon-limiting examples and with reference to the accompanying drawings,in which:

FIG. 1 is a general view of an E-UTRAN system,

FIG. 2 is a view illustrating transmission of layered multimedia data inaccordance with a first embodiment,

FIG. 3 is a view illustrating transmission of layered multimedia data inaccordance with a second embodiment,

FIG. 4 is a view illustrating transmission of layered multimedia data inaccordance with a third embodiment,

FIG. 5 is a view illustrating timing of transmission of layered data,and

FIG. 6 is a view of an E-UTRAN system configured for transmittinglayered multimedia data.

DETAILED DESCRIPTION

If layered multimedia is used for SFN transmission, the system needs todefine different MBSFN areas for each layer of the multimedia stream.The MBSFN area where the higher layers of the media stream are broadcastis a subset of the MBSFN area where the lower layers are broadcast. Thiswould allow, for instance, a use case where higher layers of a mediastream is broadcast only in certain parts of the network, e.g., in hotspots thereby, enabling a high quality media reception, while in therest of the network, e.g., in the macro cells only the base layer of themedia stream is broadcast. See also the international patent applicationNo. PCT/EP2005/009387.

A further possibility to optimize the transmission when distributinglayered media in MBSFN is to use different transport formats i.e.,modulation and coding for the transmission of the different layers, seealso PCT/EP2005/009387. Thereby, the amount of radio resources spent onthe MBSFN transmission can be decreased in exchange for some compromisein the quality of the received media stream. That is, by sacrificingthat the media stream will not be received with highest quality in thewhole MBSFN area, some radio resources spent on MBSFN broadcast can besaved. This is a trade-off that can be utilized via the layered mediaconcept.

However, the current specification of the MBMS services proposed forE-UTRAN does not allow for layered media when transmitting MBMS data.Although there exists the straight-forward solution of deliveringlayered media in MBMS by the MBSFN transmission mode concept, suchmethods do not enable the system to take into account UE feedbacks inoptimizing the transmission of the different layers and do not considersingle-cell transmission modes and their combination with MBSFNtransmission when optimizing for layered media delivery.

By not considering the different needs of the different layers in themedia stream, the E-UTRAN MBMS transmission methods will not be able toadapt the required radio resources to the different media stream layersand thereby they will fail to achieve better utilization of radioresources.

With reference to FIGS. 2, 3 and 4 and in accordance with the presentinvention support is added to the signaling channels, protocols, etc.,for example, information elements on the MCCH channel, and signalingmeans 202 for each of the different MBMS transmission modes defined foran E-UTRAN system 200, which are required for the differentiatedhandling of the different media layers during the transmission. Theaddition of support for MBMS transmission in an E-UTRAN system makes itpossible to take into account the radio channel conditions of receivingUEs 203 when deciding which components of the media stream to transmitand what transmission parameters to use such as transmission power,coding, etc. Below transmission for different transmission modes aredescribed.

In the single cell PTM without feedback mode, the application of layeredmedia allows the system to employ different transport formats and/ortransmit powers for the broadcast of the different layers of the mediastream. With reference to FIG. 2, the base layer or lower layers can bebroadcast with high enough power in a data stream 205 from the eNodeB201 to a UE 203 and with an appropriate transport format such that thetransmission can be received with high probability even at the celledge. Then the higher media layers can be broadcast with lower power ina data stream 207 in order to decrease the interference caused toneighbor cells and/or with a less protective transport format in orderto save radio resources in the cell.

In the single cell PTM without feedback mode, the eNodeB 201 may also beenabled to suspend the transmission of higher media layers if it doesnot have enough resources or an unacceptably high interference is causedto neighbor cells. For the coordination of resources used for the PTMtransmission in the neighbor cells (e.g., to control interference),either the MCE could coordinate which radio resources to be used for PTMtransmission in neighbor cells or the neighbor eNodeBs could negotiateit among themselves.

In accordance with one embodiment an indication for each transport blockis sent on the radio interface to which layer it belongs to. Hereby theUE can decode the transport block according to the appropriate transportformat. For this purpose it is possible to indicate the layerinformation either as part of the scheduling information sent on MCCH.Alternatively, in accordance with another embodiment, when the MCCH/MTCHlogical channels are mapped onto the DL-SCH, the layer information canbe indicated via the L1/L2 control signaling used to address thescheduled UE in the DL-SCH. This can for example be performed by using aseparate group RNTI (Radio Network Temporary Identity) for each layerwhen addressing the recipient of the data sent on DL-SCH.

In the single cell PTM with feedback transmission mode, a similarsolution can be applied as for the no-feedback case. However inaddition, the UE 203 can be configured to transmit feedback informationrelating to the channel conditions in a message 209. The eNodeB 201 canuse also feedback information from the UEs when selecting transmissionparameters, such as transport format and transmit power, to be used forthe transmission of the different layers in subsequent datatransmissions 211 and 213. The selection may include the decision onwhether to transmit a certain layer at all. Similarly as in the singlecell PTM without feedback mode, the transmission of a given layer can bedependent also on the interference conditions caused to neighbor cells.

The UEs can send feedback information on the measured reference signalpower that can be used by the eNodeB to estimate the path loss towardthe UEs and set the transmission power and/or transport formataccordingly. Other feedback information such as Channel QualityIndicator (CQI) feedback may also be used for this purpose. In addition,information about the UE capabilities such as the screen size, etc. mayalso be used by the eNodeB to decide which layers to broadcast.

The channel quality information received from the UE can be based onregular handover measurement reports, such as a measured referencesignal power. The channel quality information received from the UE canalso be based on a Channel Quality Indicator (CQI) reporting similar oreven the same as used for channel reporting in case of unicast traffic.The UE may have unicast traffic ongoing in parallel with the MBMSreception, and then the unicast channel reporting may be used for MBMSpurposes as well.

Also, the channel quality information may be coupled to the countingmechanism, which used to identify how many UEs are interested in a givenservice. In that case the channel quality information can be transmittedtogether with the counting information.

In the Hybrid transmission with MBSFN and Single Cell PTM mode, whichcan be regarded as a combination of MBSFN transmission and single cellPTM transmission, the base layer or the lower layers of the media streamcan be sent in MBSFN mode in the given MBSFN area in transmissions 215.As a result all users will be able to receive the media stream with somebase quality in the entire MBSFN area. Then, in addition each eNodeB mayor may not be configured to broadcast the higher layer media componentsin single cell PTM mode in a transmission 217. This can be performedwith or without feedback from a UE 203. This allows for each eNodeB 201to decide autonomously based on its available radio resources andpotentially using feedback information from UEs whether it wants tobroadcast the higher layers or not.

In accordance with one embodiment a base station, i.e. the eNodeB, cantake into account the own traffic load both unicast and existingmulticast when deciding to transmit higher layers. Also UE feedbackinformation both channel feedback and counting information and possiblyalso the interference caused to neighbor cells can be taken into accountwhen a base station decides which layers to transmit in PTM or MBSFNmode or whether to transmit anything in PTM mode at all.

The time-frequency resource in which the higher layers are broadcast insingle cell PTM mode can for example be selected by a scheduler in theeNodeB. If these resources are selected autonomously by the eNodeBs, thePTM transmission of neighbor eNodeBs may cause interference to eachother. In order to avoid a high interference level, the eNodeBs mayregulate the maximum power spent on PTM broadcast and may also adjustthe transmitted power level based on feedback information from the UEs.In accordance with one embodiment the MCE can be configured to act as acoordinator to avoid such interference.

For example, the UEs may send measurement reports on received referencesignal power, for example the same used for handover measurements, whichcan be used by the eNodeB to obtain the path loss toward the UEs andadjust the downlink transmit power accordingly. This feedback, i.e., themeasurement report can be sent either via the signaling bearer, e.g. viaregular RRC protocol signaling or combined with the counting informationas part of the MBMS counting procedure.

When sending the higher layer media components with the single cell PTMtransmission mode the eNodeB is preferably configured to take care ofthe timing of the transmission in relation to the MBSFN transmissionsuch that when the data belonging to the higher media layers arereceived in the UE it is not yet outdated and can be presented to theuser at the UE combined with the base layer data received via the MBSFNtransmission. The UE can reorder packets in the playout buffer, ifnecessary. However, this requires the E-UTRAN network to keep the delaybelow the delay tolerance of the playout buffer of the UE.

Upon the start of the service it has to be signaled to the UEs where aUE can find the transmission of the different media layers belonging tothe same service, i.e. whether a given layer is transmitted in the MBSFNmode or in the single cell broadcast mode. The signaling can provide thecoupling between the layers sent with the different transmission modes,i.e., creating the coupling between the IDs used in the differenttransmission modes for the identification of the different streams(connections). This signaling may need to be repeated periodically orsent dedicated to each UE newly entering the cell.

FIG. 5 shows the timeline of the radio interface transmission of theMBSFN and the PTM transport blocks in the hybrid transmission scenario.It can be seen, that since the minimum quality of the media is to beprovided for all UEs (at least) the base layer has to be sent in MBSFNmode in order to reach even the cell edge UEs. Furthermore in each cellthe eNodeBs can optimize the distribution of higher layers by PTMtransmission mode. In FIG. 2 the PTM mode is used for the twoenhancement layers above the base (Enh#1 and Enh#2).

FIG. 6 shows the network view of the MBSFN transmissions plus the PTMtransmissions in individual cells. The base layer is distributed byMBSFN within the whole area, while individual cells can optimize thetransmission of higher layers locally.

For the optimized distribution of the media layers the Evolved PacketCore network preferably provides the eNodeB information on which layer aparticular IP packet belongs to. That is, the IP packets should carrythe corresponding layer ID. This can be provided by either GTP tunnelsor by sending each media layer to different IP multicast group addresses

If GTP tunnels are used, a tunnel between the MBMS GW and the eNodeBsshould be established for each transmitted layer. The eNodeBs should beindicated which tunnel corresponds to which layer.

If IP multicast addresses are used to differentiate the layers the validrange of IP multicast addresses corresponding to the given serviceshould be indicated to the eNodeBs. In case the MBMS GW is attacheddirectly to the IP-MB, this layer ID indication method is rather simplesince the multicast routing protocols (e.g., PIM-SM) usually forward thelayers on the IP-MB as individual streams each addressed to differentmulticast groups. If the MBMS GW does not receive the media stream insuch a way, GTP tunneling can be used.

The transmission on the transport network can be either unicast or IPmulticast. However, the applied method strongly depends on whichtransmission mode is used in the access part. In MBSFN transmission modeIP multicast can be used. This enables the operator to save resources onthe transport compared to simple unicast transmission. If PTM mode isused either unicast or multicast transmission can be applied. In Hybridmode the base layer(s) can be multicast (because of the MBSFN) whilehigher layers can be chosen to be unicast or multicast.

The invention claimed is:
 1. An Evolved Universal Terrestrial Radio Access Network (E-UTRAN) system transmitting Multimedia Broadcast Multicast Service (MBMS) data, the system comprising: a base station for transmitting the MBMS data as layered data comprising a lower layer in a first transmit stream and a number of higher enhancements layers in a second transmit stream different from the first transmit stream; and signaling circuitry for transmitting control information comprising signaling that binds together the different layers transmitted in the first and second transmit streams and belonging to the same MBMS service enabling a User Equipment (UE) to reconstruct the layered MBMS data; and an entity configured to indicate to which layer data transmitted belongs.
 2. The system according to claim 1, wherein the entity for indicating to which layer data transmitted belongs is configured to transmit the indication on the MBMS point-to-multipoint Control Channel (MCCH).
 3. The system according to claim 1, wherein the entity for indicating to which layer data transmitted belongs is configured to transmit the indication via L1/L2 control signaling.
 4. The system according to claim 1, wherein the entity for indicating to which layer data transmitted belongs is configured to transmit the indication in a Media Access Control (MAC) header.
 5. The system according to claim 1, wherein the UE is configured to transmit feedback information relating to the channel quality.
 6. The system according to claim 5, wherein the system is adapted to select transport format based on information relating to the channel quality received from the UE.
 7. The system according to claim 6, wherein the system is adapted to use regular handover measurement reports as input information when selecting transport format.
 8. The system according to claim 1, wherein the system is configured to employ different transport formats or transmit powers, for transmitting the different layers of the MBMS data.
 9. The system according to claim 8, wherein the system is adapted to transmit the higher media layers in the second transmit stream with lower power than lower media layers in the first transmit stream.
 10. The system according to claim 1, wherein, when the system is configured in a Multi Broadcast Single Frequency Network (MBSFN), transmission mode, the system is configured to transmit a base layer or lower layers of the MBMS data in MBSFN mode in a given MBSFN area.
 11. The system according to claim 10, wherein the system is configured to transmit higher layer media components in single cell Point to Multipoint (PTM) mode with or without feedback.
 12. The system according to claim 11, wherein the system is configured to transmit higher layer media components in single cell Point to Multipoint (PTM) mode based on any one or more of the traffic load in a given base station, UE feedback information, or the interference caused to neighbor cells.
 13. The system according to claim 11, wherein the system is configured coordinate the PTM allocations in neighbor cells in order to avoid excessive interference either via base station to base station negotiation or via coordination from a central MBMS Control entity (MCE).
 14. A method of transmitting Multimedia Broadcast Multicast Service (MBMS) data Evolved Universal Terrestrial Radio Access Network (E-UTRAN) system, said method comprising: transmitting the data as layered data comprising a lower layer in a first transmit stream and a number of higher enhancements layers in a second transmit stream different than the first transmit stream; signaling control information, comprising signaling that binds together the transmission of the different layers in the first and second transmit streams belonging to the same MBMS service, from the system enabling a User Equipment (UE) to reconstruct the layered MBMS data; and transmitting data indicating to which layer layered data belongs.
 15. The method according to claim 14, further comprising transmitting the data indicating to which layer layered data belongs on the MBMS point-to-multipoint Control Channel (MCCH).
 16. The method according to claim 14, further comprising transmitting the data indicating to which layer layered data belongs is transmitted via L1/L2 control signaling.
 17. The method according to claim 14, further comprising transmitting the data indicating to which layer layered data belongs in a Media Access Control (MAC) header.
 18. The method according to claim 14, further comprising receiving feedback information relating to the channel quality from the UE.
 19. The method according to claim 18, further comprising selecting a transport format based on the feedback information from the UE.
 20. The method according to claim 19, further comprising using regular handover measurement reports as input information when selecting transport format.
 21. The method according to claim 14, wherein different transport formats or transmit powers are used for transmission of different layers of the MBMS data.
 22. The method according to claim 21, wherein higher media layers in the second transmit stream are transmitted with lower power than lower media layers in the first transmit stream.
 23. The method according to claim 14, wherein, when the system is configured in a Multi Broadcast Single Frequency Network (MBSFN), transmitting a base layer or lower layers of the MBMS data in MBSFN mode in a given MBSFN area.
 24. The method according to claim 23, wherein higher layer media components are transmitted in single cell Point to Multipoint (PTM) mode with or without feedback.
 25. The method according to claim 24, wherein higher layer media components are transmitted in single cell Point to Multipoint (PTM) mode based on at least one of a current traffic load for a base station, UE feedback information, or the interference caused to neighbor cells.
 26. The method according to claim 24, wherein the PTM allocations in neighbor cells is coordinated via base station to base station negotiation or via coordination from a central MBMS Control entity (MCE) in order to avoid excessive interference.
 27. A base station for use in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) system transmitting Multimedia Broadcast Multicast Service (MBMS) data, said base station comprising: a transmitter for transmitting the MBMS data as layered data comprising a lower layer and a number of higher enhancements layers, wherein the lower layer is transmitted in a first transmit stream, and wherein the number of higher enhancements layers are transmitted in a second transmit stream different from the first transmit stream; signaling circuitry associated with the transmitter, for transmitting control information comprising signaling that binds together the transmission of the different layers in the first and second transmit streams and belonging to the same MBMS service enabling a User Equipment to reconstruct the layered MBMS data; and an entity configured to indicate to which layer data transmitted belongs.
 28. The base station according to claim 27, wherein the entity for indicating to which layer layered data belongs is configured to transmit the indication on the MBMS point-to-multipoint Control Channel (MCCH).
 29. The base station according to claim 27, wherein the entity for indicating to which layer layered data belongs is configured to transmit the indication via L1/L2 control signaling.
 30. The base station according to claim 27, wherein the entity for indicating to which layer layered data belongs is configured to transmit the indication in a Media Access Control (MAC) header.
 31. The base station according to claim 27, wherein the base station is configured to receive feedback information relating to the channel quality from a UE in the E-UTRAN system.
 32. The base station according to claim 31, wherein the base station is adapted to select a transport format based on information relating to the channel quality received from the UE.
 33. The base station according to claim 32, wherein the base station is adapted to use regular handover measurement reports as input information when selecting transport format.
 34. The base station according to claim 27, wherein the base station is configured to employ different transport formats or transmit powers, for transmitting the different layers of the MBMS data.
 35. The base station according to claim 34, wherein the base station is adapted to transmit the higher media layers in the second transmit stream with lower power than lower media layers in the first transmit stream.
 36. The base station according to claim 27, wherein, when the system is configured in a Multi Broadcast Single Frequency Network (MBSFN) transmission mode, the base station is configured to transmit a base layer or lower layers of the MBMS data in MBSFN mode in a given MBSFN area.
 37. The base station according to claim 36, wherein the base station is configured to transmit higher layer media components in single cell Point to Multipoint (PTM) mode with or without feedback.
 38. The base station according to claim 37, wherein the base station is configured to transmit higher layer media components in single cell Point to Multipoint (PTM) mode based on one or more of the traffic load in a given base station, UE feedback information, or the interference caused to neighbor cells.
 39. The base station according to claim 37, wherein the base station is configured coordinate the PTM allocations in neighbor cells in order to avoid excessive interference either via base station to base station negotiation or via coordination from a central MBMS Control (MCE) entity.
 40. A User Equipment (UE) for use in an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) system transmitting Multimedia Broadcast Multicast Service (MBMS) data, said UE comprising: a receiver for receiving the MBMS data as layered data in first and second different transmit streams, wherein the first transmit stream comprises a lower layer of the MBMS data and wherein the second transmit stream comprises a number of higher enhancements layers of the MBMS data; processing circuitry for receiving control information via said receiver, said control information comprising signaling that binds together the transmission of the different layers in the first and second transmit streams belonging to the same MBMS service, thereby enabling the UE to reconstruct the layered MBMS data; and wherein the UE is configured to receive an indication on a MBMS point-to-multipoint Control Channel (MCCH), indicating to which layer layered data belongs.
 41. The UE according to claim 40, wherein the UE is configured to receive an indication via L1/L2 control signaling, indicating to which layer layered data belongs.
 42. The UE according to claim 40, wherein the UE is configured to receive an indication in a Media Access Control (MAC) header, indicating to which layer layered data belongs.
 43. The UE according of claim 40, wherein the UE includes a transmitter and is configured to transmit, via said transmitter, feedback information relating to the channel quality.
 44. The UE according to claim 40, wherein, when the system is configured in a Multi Broadcast Single Frequency Network (MBSFN), transmission mode, the UE is configured to receive a base layer or lower layers of the MBMS data in MBSFN mode in a given MBSFN area.
 45. The UE according to claim 44, wherein the UE is configured to receive higher layer media components in single cell Point to Multipoint (PTM) mode with or without feedback. 